Fluid end for positive displacement pump systems

ABSTRACT

Aspects of the disclosure generally relate to positive displacement pumps, and more specifically to fluid end designs for plunger pumps typically used to stimulate oil and natural gas wells underground shale formations by means of hydraulic fracturing (also referred to as fracing or fracking). The fluid end designs include an intersection-less fluid end having an inline discharge and suction valve assembly. The fluid end designs an in-line suction and discharge valve assembly.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims benefit of and incorporates the entire contents of U.S. Provisional Patent Application 63/283,890, titled “Fluid End For Positive Displacement Pump Systems,” filed on Nov. 29, 2021.

BACKGROUND Field

Embodiments of the disclosure generally relate to positive displacement pump systems, and more specifically to fluid ends of plunger pumps typically used to stimulate oil and gas wells underground shale formations by means of hydraulic fracturing (also referred to as fracing or fracking).

Description of the Related Art

High-pressure, reciprocating, plunger pumps have been the primary pumps used from oil fields early beginnings until now. These high-pressure pumps operate at very high hydraulic horsepower flow rates and pressure levels and are the ongoing backbone workhorse pump in the well services industry today. These high-pressure pumps have fluid ends that often operate and produce pressurized fluid flow of fracking chemical solutions and proppants in excess of 15,000 pounds per square inch, which produces high internal stress levels in the fluid ends.

Pump fluid ends used for oilfield well stimulation and fracking are continually subject to harsh environments and operating conditions. These include pumping at high cavitation levels, internal damage caused by pumping corrosive chemical mixtures and acids, damage and wear from pumping high volumes of abrasive proppants used during fracking, internal damage and wear caused by long service periods and metal fatigue operating under heavy loads, high flow rates and pressures, pressure pumping while using poor and or inconsistent fluid charge supply, and operating with poor and/or improper maintenance. The above mentioned severe operating conditions, in addition to other operating practices and conditions, result in fluid end damage, operating failures, and short or reduced service lives, thereby reducing reliability and increasing maintenance cost.

In view of the foregoing and other considerations, the embodiments described in this disclosure result from the desire to provide a fluid end for the oilfield well service industry that operates under the aforementioned severe operating conditions while providing a long service life without failures. Moreover, the desire is to provide a fluid end that supports the oilfield services industry enabling it to better thrive by improving and increasing operating efficiencies with sustainable performance improvements. And finally, the desire is to provide a fluid end that is easy to operate, maintain, repair and service in the field, as well as a monitoring system for predictive maintenance to eliminate premature shutdown and evaluation procedures to diagnose operating issues.

SUMMARY

In one embodiment, a fluid end system comprises a fluid end body; an inline discharge and suction valve assembly disposed in the fluid end body; a hollow plunger coupled to the fluid end body; a fluid displacement cylinder disposed around at least a portion of the hollow plunger; and a seal assembly disposed between an outer surface of the hollow plunger and an inner surface of the fluid displacement cylinder, thereby forming a displacement chamber within the hollow plunger and the fluid displacement cylinder.

In one embodiment, a fluid end system comprises a fluid end body; an inline discharge and suction valve assembly disposed in the fluid end body; a hollow plunger coupled to the fluid end body; a fluid displacement cylinder coupled to the hollow plunger; and a seal assembly disposed between the fluid displacement cylinder and the hollow plunger, thereby forming a displacement chamber at least partially within the fluid displacement cylinder and/or the hollow plunger.

In one embodiment, a fluid end system comprises a fluid end body; a suction valve member disposed in the fluid end body and movable between an open and a closed position; a discharge valve member disposed in the fluid end body and movable between an open and a closed position; and a valve seat disposed in the fluid end body, wherein the discharge valve member seals against the valve seat when in the closed position, and wherein the suction valve member seals against the discharge valve member when in the closed position.

In one embodiment, a fluid end system comprises a fluid end body; a suction valve member supported by a first valve guide and a second valve guide; a discharge valve member disposed in the fluid end body; a suction valve biasing member biasing the suction valve member into contact with the discharge valve member; and a discharge valve member biasing the discharge valve member into contact with a valve seat disposed in the fluid end body.

In one embodiment, an inline discharge and suction valve assembly comprises a suction valve member and a biasing member that forces the suction valve member in a first direction; a discharge valve member and a biasing member that forces the discharge valve member in a second, opposite direction, wherein a central axis of the suction valve member is aligned with a central axis of the discharge valve member; and a valve seat, wherein the discharge valve member seals against the valve seat, and wherein the suction valve member seals against the discharge valve member.

In one embodiment, an inline discharge and suction valve assembly comprises a suction valve member and a biasing member that forces the suction valve member in a first direction; a discharge valve member and a biasing member that forces the discharge valve member in a second, opposite direction; and a valve seat, wherein the discharge valve member seals against the valve seat, and wherein the suction valve member is movable with the discharge valve member when the discharge valve member moves from a closed position to an open position.

In one embodiment, an inline discharge and suction valve assembly comprises a suction valve member movable between an open and closed position; and a discharge valve member movable between an open and closed position, wherein a central axis of the suction valve member is aligned with a central axis of the discharge valve member, and wherein the suction valve member moves with the discharge valve member when the discharge valve member moves to the open position.

In one embodiment, a method of operating a fluid end system comprises pumping fluid into a displacement chamber of a hollow plunger, wherein the fluid pressure forces a suction valve member into an open position to allow fluid to flow into the displacement chamber; and pumping the fluid out of the displacement chamber, wherein the fluid pressure forces a discharge valve member into an open position to allow fluid to flow out of the displacement chamber, wherein the suction valve member remains in contact with the discharge valve member when the discharge valve member is moved into the open position.

In one embodiment, a method of operating a fluid end system comprises forcing a suction valve member into a closed position against a discharge valve member; forcing the discharge valve member into a closed position against a valve seat, wherein a central axis of the suction valve member is aligned with a central axis of the discharge valve member; moving a fluid displacement cylinder in a first direction relative to a hollow plunger to draw fluid into a displacement chamber, wherein the fluid pressure forces the suction valve member into an open position to allow fluid to flow into the displacement chamber; and moving the fluid displacement cylinder in a second, opposite direction relative to the hollow plunger to push the fluid out of the displacement chamber, wherein the fluid pressure forces the discharge valve member into an open position to allow fluid to flow out of the displacement chamber, wherein the suction valve member remains in contact with discharge valve member when the discharge valve member is moved into the open position.

In one embodiment, a fluid end monitoring system comprises a fluid end body; a discharge valve member disposed in the fluid end body; a suction valve member disposed in the fluid end body and movable into a closed position, wherein the suction valve member seals against the discharge valve member when in the closed position; and a measurement device configured to measure a position of the suction and discharge valve members within the fluid end body.

In one embodiment, a method of operating a pump system comprises pumping pressurized fluid from one or more inlets of a fluid end body into a chamber of a cylinder housing, wherein the pressurized fluid forces a suction valve member into an open position to allow fluid flow into the chamber; and pumping the pressurized fluid from the displacement chamber into one or more outlets of the fluid end body, wherein the pressurized fluid forces a discharge valve member into an open position to allow fluid flow out of the chamber, wherein the suction valve member remains in contact with the discharge valve member when the discharge valve member is moved into the open position.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments.

FIG. 1A is a sectional view of a pump system, according to one implementation.

FIG. 1B is a sectional view of a fluid end of the pump system shown in FIG. 1A, according to one implementation.

FIG. 2 is a sectional view of a portion of the fluid end showing a suction and discharge valve assembly, according to one implementation.

FIG. 3 is another sectional view of the portion of the fluid end showing the suction and discharge valve assembly, according to one implementation.

FIG. 4 is another sectional view of a portion of the suction and discharge valve assembly, according to one implementation.

FIG. 5 is another sectional view of the suction and discharge valve assembly during suction, according to one implementation.

FIG. 6 is another sectional view of the suction and discharge valve assembly during discharge, according to one implementation.

FIG. 7 is another sectional view of a portion of the suction and discharge valve assembly, according to one implementation.

FIG. 8 is another sectional view of the fluid end having a measurement device, according to one implementation.

FIG. 9 is another sectional view of a portion of the fluid end having the measurement device, according to one implementation.

FIG. 10 is another sectional view of a portion of the fluid end having the measurement device, according to one implementation.

FIG. 11 is another sectional view of the measurement device, according to one implementation.

FIG. 12 is an enlarged sectional view of a portion of the measurement device, according to one implementation.

FIG. 13 is another sectional view of a portion of the fluid end having the measurement device during suction, according to one implementation.

FIG. 14 is another sectional view of a portion of the fluid end having the measurement device during discharge, according to one implementation.

FIG. 15 is a sectional view of a pump system, according to one implementation.

FIG. 16 is a sectional view of a portion of the pump system, showing a suction and discharge valve assembly, according to one implementation.

To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one implementation may be beneficially utilized on other implementations without specific recitation.

DETAILED DESCRIPTION

Aspects of the disclosure relate to pumping systems, apparatus, and related methods. Specifically, this disclosure relates to new and improved fluid end designs. This disclosure incorporates the entire contents of U.S. Provisional Patent Application 63/231,409, titled “Pump Fluid End Intersection-Less,” filed on Aug. 10, 2021.

The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include but are not limited to welding, interference fitting, and/or fastening such as by using bolts, threaded connections, pins, and/or screws. The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include but are not limited to integrally forming. The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include but are not limited to direct coupling and/or indirect coupling. The disclosure contemplates that terms such as “couples,” “coupling,” “couple,” and “coupled” may include operable coupling such as electric coupling and/or fluidly coupling.

Embodiments of the fluid end designs described herein can be used with oilfield frac pumps, in addition to other industries that use positive displacement pumping systems with fluid ends for any and all types of fluid flow pumping.

In one embodiment, a fluid end with no internal intersections is described herein. The fluid end comprises (i) valves positioned in-line horizontally, (ii) hollow plungers with incorporated discharge valves, (iii) reciprocating displacement cylinders, (iii) displacement cylinders which attach to pump power end crossheads, and (iv) no discharge access covers or related seal covers. The fluid end replaces high cost valve over valve fluid end seat and packing areas with low cost components that are easy to change and repair in the field.

Advantages of the fluid end with no internal intersections according to the embodiments described herein include but are not limited to increased flow outputs, longer service life, fast easy maintenance, less downtime, easy field repairs and replacements of all critical parts, and light (reduced) weight.

Additional advantages of the intersection less fluid end design include, but are not limited to, having balanced forces, reduced internal stress, increased fatigue life, increased flow outputs due to straight line flow, increased fluid end life due to the intersection-less design, smaller main body forgings with greatly reduced weight, and easier maintenance and support.

Additional advantages of the intersection less fluid end design include, but are not limited to the following. A balanced valve design that reduces valve seat wear and internal stress level. A larger discharge valve opening area that minimizes or eliminates excessive flow velocity that causes fluid end damage, seat jetting, and fluid end erosion, all the result of using discharge valves that are too small. A fast valve and seat change suitable for the oilfield industry, the seat being less than a foot from the access port, allowing quick and easy access, inspection and service, and no more rolling the pump to clear plungers for valve and seat access. Reduced consumables by using a single valve seat for suction and discharge. A straight line suction flow path that is precision engineered to insure maximum fluid intake and filling. Dual guided valves that ensure maximum performance. The lowest cost fluid end to support and maintain. The lightest 2500-3000 Horsepower high pressure fluid end, being less than (e.g. half) the weight of standard valve over valve fluid ends.

FIG. 1A is a sectional view of a pump system 100, according to one implementation. The pump system 100 may be a high-pressure positive displacement pump system configured to pump fracking fluid into a wellbore to conduct a hydraulic fracturing operation on a subterranean oil and gas formation. The pump system 100 includes a power end 10 coupled to a fluid end 20. The power end 10 may be any type of power system configured to operate the pump system 100. The fluid end 20 is a novel, intersection less fluid end design for high pressure oilfield well stimulation applications, especially hydraulic fracturing.

The power end 10 includes a crankshaft 1 that is coupled to a crosshead assembly 2, which is connected to a connecting rod 3. A plurality of stay rods 4 are used to couple the fluid end 20 to a housing 5 of the power end 10. The connecting rod 3 is coupled to a fluid displacement cylinder 21 of the fluid end 20 via a clamp 6. The power end 10 is configured to drive (e.g. push and pull) the connecting rod 3 back and forth, which also moves the fluid displacement cylinder 21 of the fluid end 20 back and forth. As the fluid displacement cylinder 21 reciprocates, fluid is pumped through the fluid end 20. Specifically, as the fluid displacement cylinder 21 is moved in a first direction toward the power end 20, fluid is drawn into one or more inlets 22 of a body 23 of the fluid end 20. As the fluid displacement cylinder 21 is moved in a second, opposite direction away from the power end 20, fluid is discharged out of one or more outlets 27 of the body 23 of the fluid end 20.

FIG. 1B is a sectional view of the fluid end 20 of the pump system 100 shown in FIG. 1A, according to one implementation. The fluid end 20 includes the fluid displacement cylinder 21, which is disposed around and moves relative to a hollow plunger 25. The hollow plunger 25 is coupled (such as by one or more bolts 26) to the body 23 of the fluid end 20. A seal assembly 24 provides a seal between the fluid displacement cylinder 21 and the hollow plunger 25, and includes a plurality of dynamic seals 24A positioned between an inner surface of the fluid displacement cylinder 21 and an outer surface of the hollow plunger 25. A retainer nut 24B may be coupled to an end of the fluid displacement cylinder 21 to retain the plurality of dynamic seals 24A between the fluid displacement cylinder 21 and the hollow plunger 25. In an alternative embodiment, the positions of the fluid displacement cylinder 21 and the hollow plunger 25 can be reversed such that the fluid displacement cylinder 21 is disposed and reciprocates within the hollow plunger 25.

A displacement chamber 29 is formed by the interior areas of the fluid displacement cylinder 21 and the hollow plunger 25. Fluid is pumped into and out of the displacement chamber 29 during operation of the pump system 100. A suction and discharge valve assembly 30 is disposed within the body 23 of the fluid end 20 between the hollow plunger 25 and a cover nut 28. The cover nut 28 is coupled (such as threaded and/or bolted) to the body 23 of the fluid end 20 and can be removed to provide immediate and easy access to the suction and discharge valve assembly 30.

In one embodiment, a liner may be added to the inner diameter of the hollow plunger 25 to adapt the fluid end 20 with various pump designs. In one embodiment, the inner diameter of the hollow plunger 25 and/or the liner can be machined to have a spiral pattern that creates a spiral, vacuum type fluid flow when pressurized fluid is drawn into the displacement chamber 29. A change in the inner diameter of the hollow plunger 25 will also change pump flow output.

FIG. 2 is a sectional view of a portion of the fluid end 20, specifically the suction and discharge valve assembly 30, according to one implementation. The suction and discharge valve assembly 30 uses a unique valve in valve design. As further described below, both the suction and discharge valves are positioned so that the suction and discharge valve members share a common valve seat. The net result is a common operating centerline that allows the suction and discharge valve members to function both independently and together having the suction valve member inside the discharge valve member. There are no solid plungers that cross paths perpendicular to the suction or discharge valve members, which enables the straight-line valve in valve configuration. The suction and discharge valves are supported by mechanical valve guides to ensure correct contact/seating during operation, in addition to valve springs to ensure proper closure.

The suction and discharge valve assembly 30 includes a suction valve member 31 supported by a first valve guide 32, a second valve guide 35, and a biasing member shown as a valve spring 33 that biases the suction valve member into a closed position. The suction and discharge valve assembly 30 also includes a discharge valve member 34 supported by the second valve guide 35, and a biasing member shown as a valve spring 36 that biases the discharge valve member into a closed position. A central axis of the suction valve member 31 is aligned with a central axis of the discharge valve member 34 such that the suction and discharge valve members 31, 34 share common valve operating centerlines. The discharge valve member 34 may also be supported by a rod seal member 39A, which provides a seal between the inner surface of the body 23 of the fluid end 20 and an outer surface of the discharge valve member 34. One or more spacers 39B may be positioned between the rod seal member 39A and the second valve guide 35 to support and secure the rod seal member 39A within the body 23 of the fluid end 20. A portion of the suction valve member 31 may also be supported by and extend into the second valve guide 35.

The discharge valve member 34 contacts and seats against a common valve seat 37 when in the closed position. A seal member 38 may be coupled to the discharge valve member 34, which contacts and seats against the valve seat 37 when in the closed position. The suction valve member 31 contacts and seats against the discharge valve member 34 when in the closed position. The suction valve member 31 contacts and seats against the seal member 38 when in the closed position. The seal member 38 may or may not be used, and a portion of the discharge valve member 34 and/or a portion of the seal member 38 may contact and seat against the valve seat 37. The seal member 38 may or may not be used, and the suction valve member 31 may contact and seat against a portion of the discharge valve member 31 and/or a portion of the seal member 38. One or more seal members 38 may be used and may be coupled to the discharge valve member 34, the suction valve member 31, and/or the valve seat 37. In one embodiment, the seal member 38 may be two separate seal members coupled to the discharge valve member 34. For example, a first seal member disposed between the discharge valve member 34 and the valve seat 37, and a second, separate seal member disposed between the discharge valve member 34 and the suction valve member 31.

FIG. 3 is another sectional view of the portion of the fluid end 20 showing the suction and discharge valve assembly 30, according to one implementation. As shown, the X-axis is along the common valve operating centerlines, which extend horizontally left and right. When the suction valve member 31 moves to the left in a suction valve opening direction, the suction valve member 31 moves from the closed position to an open position. When the discharge valve member 34 moves to the right in a discharge valve opening direction, the discharge valve member 34 moves from the closed position to an open position. The suction valve member 31 closes against the discharge valve member 34, and the discharge valve member 34 closes against the valve seat 37. Because both valve members 31, 34 remain in contact during the opening and closing of the discharge valve member 34, this enables both valve members 31, 34 to be supported by the first valve guide 32 and the second valve guide 35. Only one valve seat 37 is needed to operate two valve members, i.e. the suction and discharge valve members 31, 34.

In addition, the discharge valve member 34 is in the form of a cylindrical, hollow member that opens and closes by moving along the centerline that is shared with the X-axis and secured in place by the rod seal member 39A, which seals the high-pressure discharge fluid within the high-pressure side of the body 23 of the fluid end 20. The high-pressure discharge fluid flows out of the body 23 through the outlet 27 of the fluid end 20. The cylindrical walls of the discharge valve member 34 separates the low-pressure side of the body 23 and the high-pressure side of the body 23. The discharge valve member being hollow reduces the cross-sectional area of the discharge valve member 34 that is exposed to high pressure fluid, thereby reducing the total direct acting forces upon on the high-pressure side of the discharge valve member 34.

FIG. 4 is a sectional view of a portion of the suction and discharged valve assembly 30 of the fluid end 20, according to one implementation. Specifically, a traditional valve 200 is shown compared to the suction and discharge valve assembly 30 of the fluid end 20. The valve in valve design of the suction and discharge valve assembly 30 allows the discharge valve member 34 to be in the form of a hollow cylinder, which has a reduced cross sectional area compared to the traditional valve 200. The traditional valve 200 has a larger cross sectional area against which the high pressurized fluid on the high pressure side may act. The high pressurized fluid acting on the larger cross sectional area increases the force pushing on and holding the traditional valve 200 in a closed position, which much be overcome to move the traditional valve 200 from the closed position to the open position. In contrast, the discharge valve member 34 being hollow reduces over 12 square inches of high-pressure force on a 5-inch valve, according to one example, making the discharge valve member 34 easier to control, e.g. open. The high pressurized fluid acting on a smaller cross sectional area reduces the force pushing on and holding the discharge valve member 34 in a closed position, which is easier to overcome to move the discharge valve member 34 from the closed position to the open position (compared to the traditional valve 200).

FIG. 5 is another sectional view of a portion of the fluid end during suction, according to one implementation. FIG. 6 is another sectional view of a portion of the fluid end during discharge, according to one implementation. FIGS. 5 and 6 show the operation of the suction and discharge valve assembly 30 according to one embodiment.

As shown in FIG. 5 , the suction valve member 31 moves to the left along the X-axis, maintaining a central axis position by the first valve guide 32 and the second valve guide 35. The suction valve member 31 moves from the closed position to the open position. The suction valve member 31 moves away from and out of contact with the discharge valve member 34 and/or the seal member 38, thereby compressing the valve spring 33 and opening fluid communication between the inlet 22 and the displacement chamber 29. Specifically, as the fluid displacement cylinder 21 (shown in FIG. 1B) is moved in a direction away from the suction and discharge valve assembly 30, the pressure in the displacement chamber 29 is reduced to a pressure less than the pressure of the fluid from the inlet 22. The differential pressure on opposite sides of the suction valve member 31 is sufficient to overcome the force of the valve spring 33, thereby moving the suction valve member 31 from the closed position to the open position. The suction valve member 31 may stop against the first valve guide 32. Pressurized fluid enters from the inlet 22 flowing through the open suction valve member 31 into the hollow plunger 25 and the displacement chamber 29. The fluid flowing through the inlet 22 into the fluid end 20 may be pressurized up to 150 psi by centrifugal charge pumps supporting the low pressure side of the pump system 100.

As shown below in FIG. 6 , in a similar manner, the suction valve member 31 moves to the right along the X-axis, maintaining a central axis position by the first valve guide 32 and the second valve guide 35. The suction valve member 31 moves from the open position back to the closed position and into contact with the discharge valve member 34 and/or the seal member 38. Specifically, as the fluid displacement cylinder 21 (shown in FIG. 1B) is moved in a direction toward the suction and discharge valve assembly 30, the pressure in the displacement chamber 29 is increased to a pressure greater than the pressure of the fluid from the inlet 22. The differential pressure on opposite sides of the suction valve member 31 is sufficient to move the suction valve member 31 from the open position to the closed position with the assistance of the valve spring 33 and into contact with the discharge valve member 34. As the fluid displacement cylinder 21 (shown in FIG. 1B) continues to move in a direction toward the suction and discharge valve assembly 30, the pressure in the displacement chamber 29 is increased to a pressure greater than the pressure of the fluid from the discharge port 27. The differential pressure on opposite sides of the suction and discharge valve assembly 30 is sufficient to overcome the force of the valve spring 36, thereby moving the suction and discharge valve assembly 30 from the closed position to the open position. The suction valve member 31 remains in contact and moves with the discharge valve member 34 when the suction and discharge valve assembly 30 is moved into the open position. The discharge valve member 34 and/or the seal member 38 move away from and out of contact with the valve seat 37, thereby compressing the valve spring 36 and opening fluid communication between the displacement chamber 29 and the one or more outlets 27. The discharge valve member 34 may stop against the rod seal member 39A. Pressurized fluid in the hollow plunger 25 and the displacement chamber 29 flows out through the one or more outlets 27.

FIG. 7 is another sectional view of a portion of the suction and discharge valve assembly 30, according to one implementation. The suction and discharge valve assembly 30 is shown compared to the traditional two valve design 300. The traditional two valve design 300 requires two separate valve members 310, 320 and two separate valve seats 315, 325. In contrast, the valve in valve design of the suction and discharge valve assembly 30 has a single valve seat 37 (which may be a polyurethane valve insert for example) that seals both the suction valve member 31 and the discharge valve member 34. The valve in valve design reduces consumable costs without reducing performance due to the larger valve opening area design, which reduces flow velocity (e.g. over 60%) thus reducing wear of the valve seat 37. Although the suction and discharge valve assembly 30 is shown with only one valve seat 37, other embodiments may include two or more valve seats.

An advantage of the suction and discharge valve assembly 30 includes moving the cyclic high-pressure area typically contained within the large, expensive forged fluid end body directly into the valves, seat, hollow plunger, and fluid displacement cylinder, which are better designed to absorb and dissipate the stress forces and low-cost consumables that can be serviced and/or replaced in the field quickly. This provides two main benefits. First by reducing the risk of expensive and/or catastrophic fluid end failure due to stress cracking. And second by reducing logistics support levels in the form of excess equipment needed on site supporting catastrophic pump fluid end failures caused by stress cracking, which typically requires whole pumping units to be kept onsite remaining idle on standby to switch out with failed traditional valve over valve fluid ends that cannot be field serviced when they crack and are too large and heavy to switch out in the field.

An additional advantage of the fluid end 20 includes allowing bridle less discharge connections, wherein the discharge output connections may be accessed from one end of the fluid end. Generally, dual bridle type connections require special mountings with increased high-pressure piping connections that are much more expensive than single side connections. However, the larger discharge valve member 34 of the fluid end 20 reduces turbulence and rough pump operation as the displaced fluid flow from the discharge valve member 31 entering the main discharge flow via outlets 27 is moving at a slower velocity, allowing both flows to merge smoothly vs turbulent and rough caused by the traditional valve over valve fluid end small opening area valves, which produce high velocity (60 feet per second) discharge flow rates that are much faster than the flow rate of the combined pump discharge flow. In addition, the valve in valve design according to the embodiments described herein reduces excessive valve and seat wear caused by high velocity flow rates and higher levels of pressure forces acting on the valves and seats which are present in the traditional valve over valve fluid end designs with unbalanced valves that are too small. The valve in valve design according to the embodiments described herein includes valves and seats that perform better and last much longer without needing to add special carbide seat inserts or other expensive processes and modifications typically applied to traditional valves and seats to increase service life.

FIG. 8 is another sectional view of the fluid end 20 having a measurement device 40, according to one implementation. The measurement device 40 is configured to measure the position of the suction valve member 31 and the discharge valve member 34. Specifically, since the suction valve member 31 and the discharge valve member 34 share a common valve seat 37, resulting in common operating centerlines, then the position of both the suction and discharge valve members 31, 34 can measured using one contact point. Because the suction valve member 31 and the discharge valve member 34 remain in contact during the opening of the discharge valve member 34, then both valve movements can be measured and monitored by the same measurement device 40.

FIG. 9 is another sectional view of a portion of the fluid end 20 having the measurement device 40, according to one implementation. FIG. 10 is a further sectional view of the portion of the fluid end 20 having the measurement device 40, according to one implementation. With reference to FIGS. 9 and 10 , the measurement device 40 includes a spring-loaded contact follower mechanism coupled to the second valve guide 35 as further described below. Although the measurement device 40 is shown and described as having a spring-loaded contact follower mechanism and/or being an inductive liner transducer, the embodiments of the measurement device 40 may include any type of measurement device, sensor, transducer, and/or mechanism configured to measure the movement of the suction valve member 31 and/or the discharge valve member 34.

The measurement device 40 is configured to accurately acquire and monitor the actual and precise position and movement of the suction valve member 31 and the discharge valve member 34 within the body 23 of the fluid end 20. The position and movement of the suction valve member 31 may be measured relative its closed positon, its open position, to the discharge valve member 34, the valve seat 37, the second valve guide 35, and/or any other components or positions of the components of the fluid end 20. The position and movement of the discharged valve member 34 may be measured relative to its closed positon, its open position, the suction valve member 31, the valve seat 37, the second valve guide 35, and/or any other components or positions of the components of the fluid end 20. By proper application of the data collected by the measurement device 40 regarding the actual and precise position and movement of the suction valve member 31 and/or the discharge valve member 34, an increased pump efficiency can be achieved while reducing pump damage caused by bad valves and seats, as well as many other related operating conditions. The data collected by the measurement device 40 can also be used for predictive maintenance to eliminate premature shutdown and evaluation procedures to diagnose operating issues.

The measurement device 40 includes a contact follower 41, in the form of a shaft member that is integral with or coupled to a housing 42. The housing 42 encloses a biasing member, shown as a spring 43. A support member 44 is positioned and fixed on one side of the spring 43 to secure the spring 43 within the housing 42. A retainer 46 and a cover member 45 secure the support member 44 relative to the housing 42. The cover member 45 is coupled to the second valve guide 35 to secure and enclose the components of the measurement device 40 within the second valve guide 35. A sensor assembly 47 is coupled to the second valve guide 35 and is configured to measure the position of a magnetic track 48 that is coupled to the outer surface of the housing 42. One or more seals 49A, such as o-rings, may be positioned between the contact follower 41 and the second valve guide 35 to prevent fluid leakage into the second valve guide 35, and specifically onto the internal components of the measurement device 40. An impact seal 49B, such as an o-ring, may be coupled to the end of the housing 42 and disposed around the contact follower 41 to prevent the housing 42 from impacting against the interior of the second valve guide 38 during operation.

FIG. 11 is another sectional view of the measurement device 40, according to one implementation. FIG. 12 is an enlarged sectional view of a portion of the measurement device 40, according to one implementation. With reference to FIGS. 11 and 12 , the sensor assembly 47 may be in the form of an inductive linear transducer, which can take precise measurements of any displacement or movement of the housing 42, which is in direct contact with the suction valve member 31 via the contact follower 41. The contact follower 41 extends through a bore of the second valve guide 35 and is biased into and remains in contact with the suction valve member 31 by the force of the spring 43. One end of the spring 43, which is positioned within the housing 42, forces the housing 42 and the contact follower 41 in a direction toward the suction valve member 31. The opposite end of the spring 43 is fixed against the support member 44 and the retainer 46, which are secured to the second valve guide 35 by the cover member 45. The contact follower 41, the housing 42, and the magnetic track 48 (which is coupled to the outer surface of the housing 42) are movable relative to the second valve guide 35, the sensor assembly 47, the support member 44, the retainer 46, and the cover member 45 as the suction valve member 31 moves during operation of the pump system 100. One or more seals 60, such as o-rings, may be positioned between the second valve guide 35 and the body 23 of the fluid end 20 to seal and protect the sensor assembly 47 from internal pressurized fluids flowing through the body 23 of the fluid end 20. One or more seals 61, such as o-rings, may be positioned between the second valve guide 35 and the cover 45 to seal and protect the sensor assembly 47 from any external, environmental working conditions.

The sensor assembly 47 measures the real time position of the suction valve member 31. The sensor assembly 47 measures the real time position of the discharge valve member 34 via the suction valve member 31, which remains in contact with the discharge valve member 34 when the discharge valve member 34 moves from the closed position to the open position. Specifically, the sensor assembly 47 detects magnetic field changes in proximity relationship between a sensor 50 and the magnetic track 48. The magnetic track 48 is coupled to the housing 42. The sensor 50 is attached to a support member 51, which is coupled to the interior of the second valve guide 35 (such as by bolts or screws). A connector 52 may be used to connect the sensor 50 to a controller 53 containing components configured to receive, process, and transmit measurements taken by the sensor 50. The controller 53 may include a power source, a data export connection, a data collection integrated circuit board, a central processing unit, and/or any other components configured to receive, process, and transmit signals received by the sensor 50. Alternatively, an external power system can be used to power the controller 53.

The controller 53 may be configured to convert and/or transmit an electrical signal received from the sensor 50 so that it can be processed by various devices. The electrical signal received from the sensor 50 may correspond to the displacement of the housing 42 and/or the contact follower 41, which are biased into contact with the suction valve member 31. The electrical signal may be proportional to the displacement of the suction valve member 31 and/or the discharge valve member 34. Therefore the electrical signal can be used to calculate the position of the suction valve member 31 and/or the discharge valve member 34 during operation. The controller 53 may be an external controller that is in communication with the sensor assembly 47, and configured to receive and/or transmit electrical signals with the sensor assembly 47. The measurement device 40 and/or the controller 53 can be joined with other measurement devices, such as pressure transducers that are coupled externally to the fluid end or any other systems in fluid communication with the fluid end 20, to determine overall system health and performance.

FIG. 13 is another sectional view of a portion of the fluid end having the measurement device during suction, according to one implementation. FIG. 14 is another sectional view of a portion of the fluid end having the measurement device during discharge, according to one implementation. The cover nut 28 may also be sealed to protect the sensor assembly 47 from any external, environmental working conditions, while allowing easy access to the internal components for repairs, maintenance, connections, service, programming, updates, changes, data acquisition and transfer, among others.

The suction valve member 31 moves to the left along the X-axis into the open position, during which fluid flows from the inlet 22 through the discharge valve member 34 and into the displacement chamber 29. As the suction valve member 31 moves, the contact follower 41 remains in contact with the suction valve member 31 via the force exerted on the contact follower 41 and the housing 42 by the spring 43. As the contact follower 41 and the housing 42 move left along the X-axis, the magnetic strip 28 being coupled to the housing 42 also moves with contact follower 41. The linear movement of the contact follower 41, the housing 42, and the magnetic track 28 traces and duplicates exactly the movement of the suction valve member 31. The exact progressive movements and rates of speed are collected by the sensor 50 through magnetic encoder induction. These measurements may be recorded sequentially in nanoseconds, producing a trace record of the suction valve member 31 movements at all times.

In a similar manner, the suction valve member 31 moves to the right along the X-axis into the closed position and returning into contact with the discharge valve member 34. After which both the suction valve member 31 and the discharge valve member 34 move together at the same rate and relative positions to move the discharge valve member into the open position, during which fluid flows from the displacement chamber 29 to the one or more outlets 27. As both the suction valve member 31 and the discharge valve member 34 move, the contact follower 41 remains in contact with the suction valve member 31 via the force exerted on the contact follower 41 and the housing 42 by the spring 43. As the contact follower 41 and the housing 42 move right along the X-axis, the magnetic strip 28 being coupled to the housing 42 also moves with contact follower 41 and the spring 43 is compressed between the housing 42 and the support member 44. The linear movement of the contact follower 41, the housing 42, and the magnetic track 28 traces and duplicates exactly the movement of the suction valve member 31 and the discharge valve member 34. The exact progressive movements and rates of speed are collected by the sensor 50 through magnetic encoder induction. These measurements may be recorded sequentially in nanoseconds, producing a trace record of the suction valve member 31 and the discharge valve member 34 movements at all times.

Taking actual real time measurement of the suction and discharge valve member movements has not been performed in the oilfield industry for high pressure pumps used in hydraulic fracturing due to the difficulty involved. This is because standard valve over valve design fluid ends have separate and independent suction and discharge valves in separate low-pressure and high-pressure areas. Taking actual real time valve measurements provides the exact amount and rate the suction and discharge valve members move. These actual real time measurements provide direct volumetric pump output measurement capability, and a complete view of the actual pump efficiency. Having actual real data eliminates guessing and enables high accuracy in correctly determining pump performance levels. Additional advantages of the fluid end 20 having the measurement device 40 include but are not limited to targeted valve and seat maintenance, targeted efficiency improvements supporting best practices, reduced down time, real time status, accurate log and performance records, reduced reliance on high skilled labor for pump operation and troubleshooting, reduced need for support equipment, most accurate pump diagnostics, increased pump life span, increased safety, reduced operating costs, failure prediction. The measurement device 40 may also include a global positioning system (GPS) to track the location of the fluid end 20 and/or the pump system 100.

FIG. 15 is a sectional view of a pump system 400, according to one implementation. The pump system 400 may be a high-pressure positive displacement pump system configured to pump fracking fluid into a wellbore to conduct a hydraulic fracturing operation on a subterranean oil and gas formation. The pump system 400 includes a fluid end 420 that is coupled to a connection housing 410. Although the fluid end 420 is illustrated as being connected to a flanged end of the connection housing 410 by one or more bolts 461 and nuts 460, other types of connections may be used. An opposite flanged end of the connection housing 410 is coupled to a power end (such as power end 10 illustrated in FIG. 1 ) by one or more stay rods 404 and nuts 405, although other types of connections may be used.

A connecting rod 403, which is reciprocated back and forth by the power end, is coupled to a plunger 425 via a clamp 406. The power end pushes and pulls the connecting rod 403 and the clamp 406, which moves the plunger 425 back and forth within the connection housing 410. Specifically, the plunger 425 is reciprocated within a chamber 429 of a cylinder housing 421 that is at least partially disposed within a bore of the connection housing 410.

The cylinder housing 421 is disposed between the connection housing 410 and the fluid end 420. A seal support member 401 (such as a packing nut) is threaded into an end of the connection housing 410 about the plunger 425, which secures a seal assembly 424 (such as a packing gland comprising one or more seals) within the connection housing 410 about the plunger 425. The seal assembly 424 is disposed between and seals against the outer surface of the plunger 425 and the inner surface of the cylinder housing 421. The seal support member 401 and the seal assembly 424 prevent fluid or contaminant flow into or out of the chamber 429 of the cylinder housing 421 through the end of the connection housing 410 in which the plunger 425 extends.

The fluid end 420 comprises a fluid end body 423 having one or more inlets 422 and one or more outlets 427. The power end is configured to drive (e.g. push and pull) the connecting rod 403 back and forth, which also moves the plunger 425 back and forth. As the plunger 425 reciprocates, fluid is pumped through the fluid end 420. Specifically, as the plunger 425 is moved in a first direction toward the power end (and away from the fluid end 420), fluid is drawn into the one or more inlets 422 of the fluid end body 423. As the plunger 425 is moved in a second, opposite direction away from the power end (and toward the fluid end 420), fluid is discharged out of one or more outlets 427 of the fluid end body 423 as further described below.

A suction and discharge valve assembly 430 is disposed within the fluid end body 423 and directs the flow of fluid from the inlets 422 to the outlets 427. The suction and discharge valve assembly 430 is secured within the fluid end body 423 by a cover nut 428 and a cover seal 468. The cover nut 428 may be threaded into the fluid end body 423 to secure the cover seal 468 therein, which forms a seal to prevent fluid or contaminant flow into or out of the fluid end body 423 across the cover seal 468 and/or the cover nut 428. The cover nut 428 and the cover seal 468 can be removed to access, install, and/or remove the suction and discharge valve assembly 430.

FIG. 16 is a sectional view of a portion of the pump system 400, showing the suction and discharge valve assembly 430, according to one implementation. The suction and discharge valve assembly 430 is disposed within the fluid end body 423 between the plunger 425 and the cover seal 468. The suction and discharge valve assembly 430 uses a unique valve in valve design, similar to the suction and discharge valve assembly 30 and which provides many of the same benefits and advantages.

The suction and discharge valve assembly 430 includes a suction valve member 431 supported by a first valve guide 432, a second valve guide 435, and a biasing member shown as a valve spring 433 that biases the suction valve member 431 into a closed position. A first portion of the suction valve member 431 extends through the first valve guide 432, and a second portion of the suction valve member 431 extends through the second valve guide 435. The first valve guide 432 is coupled to and supported by the cylinder housing 421, and the second valve guide 435 is coupled to and supported by a discharge valve member 434. The suction valve member 431 is further supported by a spring retainer 462 and a locking device 470 (further described below).

The suction and discharge valve assembly 430 also includes the discharge valve member 434, which is supported by the cover seal 468 and a biasing member shown as a valve spring 436. The valve spring 436 biases the discharge valve member 434 into a closed position. The discharge valve member 434 may also be supported by a seal member 439A, which provides a seal between the inner surface of the fluid end body 423 and an outer surface of the discharge valve member 434. One or more spacers 439B may be positioned between the seal member 439A and the seal cover 468 to support and secure the seal member 439A within the fluid end body 423. One or more threaded bolts 480 may be used to couple the seal cover 468, the spacers 439B, and the seal member 439A together. A central axis of the suction valve member 431 is aligned with a central axis of the discharge valve member 434 such that the suction and discharge valve members 431, 434 share common valve operating centerlines.

The discharge valve member 434 contacts and seats against a common valve seat 437 when in the closed position. A seal member 438 may be coupled to the discharge valve member 434, which contacts and seats against the valve seat 437 when in the closed position. The suction valve member 431 contacts and seats against the discharge valve member 434 when in the closed position. The suction valve member 431 contacts and seats against the seal member 438 when in the closed position. The seal member 438 may or may not be used, and a portion of the discharge valve member 434 and/or a portion of the seal member 438 may contact and seat against the valve seat 437. The seal member 438 may or may not be used, and the suction valve member 431 may contact and seat against a portion of the discharge valve member 431 and/or a portion of the seal member 438. One or more seal members 438 may be used and may be coupled to the discharge valve member 434, the suction valve member 431, and/or the valve seat 437. In one embodiment, the seal member 438 may be two separate seal members coupled to the discharge valve member 434. For example, a first seal member disposed between the discharge valve member 434 and the valve seat 437, and a second, separate seal member disposed between the discharge valve member 434 and the suction valve member 431.

The valve spring 433 is retained between the second valve guide 435 and the spring retainer 462, which is coupled to the suction valve member 431 by the locking device 470. The valve spring 433 biases the second valve guide 435 against an inner shoulder of the discharge valve member 434, and biases the spring retainer 462 against an inner shoulder 474 of the locking device 470. A lower portion of a body 472 of the locking device 470 is inserted into the suction valve member 431. One or more locking members 473, such as pins or balls, extend outward from the lower portion of the body 472 and into engagement with one or more recesses 477 (e.g. one or more shoulders, grooves, or through holes) formed in the inner surface of the suction valve member 431 to couple the locking device 470 to the suction valve member 431. A seal member 476, such as an o-ring, may be disposed between the outer surface of the body 472 and the inner surface of the suction valve member 431 to prevent fluid or contaminant flow into the suction valve member 431. The locking device 470 includes a release button 471, that when pressed, allows the locking members 473 to retract into the body 472 to de-couple and remove the locking device 470 from the suction valve member 431. In this manner, at least the locking device 470, the spring retainer 462, the valve spring 433, the second valve guide 435, the suction valve member 431, and the discharge valve member 434 can all be coupled together and can be installed and/or removed from the fluid end body 423 as a whole assembly.

When the suction valve member 431 moves to the left in a suction valve opening direction (e.g. away from the cover seal 468), the suction valve member 431 moves from the closed position to an open position. When the discharge valve member 434 moves to the right in a discharge valve opening direction (e.g. away from the cover seal 468), the discharge valve member 434 moves from the closed position to an open position. The suction valve member 431 closes against the discharge valve member 434, and the discharge valve member 434 closes against the valve seat 437. The valve seat 437 is coupled to and supported by the cylinder housing 421. Because both valve members 431, 434 remain in contact during the opening and closing of the discharge valve member 434, this enables both valve members 431, 434 to be supported by the first valve guide 432 and the second valve guide 435. Only one valve seat 437 is needed to operate two valve members, i.e. the suction and discharge valve members 431, 434.

In addition, the discharge valve member 434 is in the form of a cylindrical, hollow member that opens and closes by moving along the centerline that is shared with the X-axis and secured in place by the seal member 439A, which seals the high-pressure discharge fluid within the high-pressure side of the fluid end body 423. The high-pressure discharge fluid flows out of the fluid end body 423 through the outlet 427. The cylindrical walls of the discharge valve member 434 separates the low-pressure side of the fluid end body 423 and the high-pressure side of the fluid end body 423. The discharge valve member 434 being hollow reduces the cross-sectional area of the discharge valve member 434 that is exposed to high pressure fluid, thereby reducing the total direct acting forces upon on the high-pressure side of the discharge valve member 434.

During a suction stroke, the plunger 425 is moved in a direction away from the suction and discharge valve assembly 430, and the pressure in the chamber 429 is reduced to a pressure less than the pressure of the fluid from the inlet 422. The differential pressure on opposite sides of the suction valve member 431 is sufficient to overcome the force of the valve spring 433, thereby moving the suction valve member 431 from the closed position to the open position. The suction valve member 431 may stop against the first valve guide 432.

Pressurized fluid enters from the inlet 422 flowing through one or more ports 463 in the second valve guide 435 and against the suction valve member 431 to open the suction valve member 431. Specifically, the suction valve member 431 moves away from and out of contact with the discharge valve member 434 and/or the seal member 438, thereby compressing the valve spring 433 and opening fluid communication between the inlet 422 and the chamber 429. The valve spring 433 is compressed between the second valve guide 435 and the spring retainer 462, which is secured to the suction valve member 431 via the locking device 470. The pressurized fluid then flows through one or more ports 462 in the first valve guide 432 into the chamber 429. The fluid flowing through the inlet 422 into the fluid end 420 may be pressurized up to 150 psi by centrifugal charge pumps supporting the low pressure side of the pump system 100.

During a discharge stroke, the plunger 425 is moved in a direction toward the suction and discharge valve assembly 430, and the pressure in the chamber 429 is increased to a pressure greater than the pressure of the fluid from the inlet 422 and the outlet 427. The differential pressure on opposite sides of the suction valve member 431 is sufficient to move the suction valve member 431 from the open position to the closed position with the assistance of the valve spring 433 and into contact with the discharge valve member 434 and/or the seal member 438. Similarly, the differential pressure on opposite sides of the discharge valve member 434 is sufficient to overcome the force of the valve spring 436, thereby moving the discharge valve member 434 from the closed position to the open position. The discharge valve member 434 may stop against the seal member 439A.

The suction valve member 431 remains in contact and moves with the discharge valve member 434 when the discharge valve member 434 is moved into the open position. The discharge valve member 434 and/or the seal member 438 move away from and out of contact with the valve seat 437, thereby compressing the valve spring 436 and opening fluid communication between the chamber 429 and the one or more outlets 427. Pressurized fluid in the chamber 429 flows out through the one or more outlets 427. The suction and discharge strokes are continuously repeated during operation of the pump system 400.

It is contemplated that one or more of the aspects disclosed herein may be combined. Moreover, it is contemplated that one or more of these aspects may include some or all of the aforementioned benefits.

It will be appreciated by those skilled in the art that the preceding embodiments are exemplary and not limiting. It is intended that all modifications, permutations, enhancements, equivalents, and improvements thereto that are apparent to those skilled in the art upon a reading of the specification and a study of the drawings are included within the scope of the disclosure. It is therefore intended that the following appended claims may include all such modifications, permutations, enhancements, equivalents, and improvements. The disclosure also contemplates that one or more aspects of the embodiments described herein may be substituted in for one or more of the other aspects described. The scope of the disclosure is determined by the claims that follow. 

1. A pump system, comprising: a fluid end body; a suction valve member disposed in the fluid end body and movable between an open and a closed position; a discharge valve member disposed in the fluid end body and movable between an open and a closed position; and a valve seat disposed in the fluid end body, wherein the discharge valve member seals against the valve seat when in the closed position, and wherein the suction valve member seals against the discharge valve member when in the closed position.
 2. The pump system of claim 1, further comprising: a first valve guide and a second valve guide supporting the suction valve member; a suction valve biasing member biasing the suction valve member into contact with the discharge valve member; and a discharge valve biasing member biasing the discharge valve member into contact with the valve seat.
 3. The pump system of claim 2, wherein the suction valve biasing member forces the suction valve member in a first direction, wherein the discharge valve biasing member forces the discharge valve member in a second, opposite direction, and wherein a central axis of the suction valve member is aligned with a central axis of the discharge valve member.
 4. The pump system of claim 2, wherein the discharge valve biasing member is disposed between the discharge valve member and a cover seal that is disposed within the fluid end body.
 5. The pump system of claim 2, further comprising: a spring retainer, wherein the suction valve biasing member is disposed between the second valve guide and the spring retainer; and a locking device, wherein one end of the locking device is coupled to the suction valve member, and wherein an opposite end of the locking device is coupled to the spring retainer to secure the suction valve biasing member between the second valve guide and the spring retainer.
 6. The pump system of claim 5, wherein the locking device comprises one or more locking members that extend outward into engagement with the suction valve member to couple the locking device to the suction valve member.
 7. The pump system of claim 6, wherein the locking device comprises a release button that allows the locking members to retract inward to de-couple the locking device from the suction valve member.
 8. The pump system of claim 1, wherein the suction valve member is movable with the discharge valve member when the discharge valve member moves from the closed position to the open position.
 9. The pump system of claim 1, further comprising: a connection housing coupled to the fluid end body; and a cylinder housing at least partially disposed within and between the connection housing and the fluid end body, wherein the valve seat is coupled to the cylinder housing.
 10. The pump system of claim 9, further comprising a plunger that extends into a chamber of the cylinder housing, wherein during a suction stroke of the plunger, pressurized fluid flows from an inlet of the fluid end body into the chamber, and wherein during a discharge stroke of the plunger, the pressurized fluid flows from the chamber into an outlet of the fluid end body.
 11. The pump system of claim 10, wherein during the suction stroke, the suction valve member moves from the closed position to the open position and out of contact with the discharge valve.
 12. The pump system of claim 11, wherein during the discharge stroke, the suction valve member remains in contact with the discharge valve member as the discharge valve member moves from the closed to the open position and out of contact with the valve seat.
 13. The pump system of claim 12, further comprising a cover seal and a cover nut configured to secure the suction valve member and the discharge valve member within the fluid end body.
 14. The pump system of claim 13, wherein the cover nut is threaded into the fluid end body against the cover seal, and wherein the cover seal is coupled to a seal member that seals between an outer surface of the discharge valve member and an inner surface of the fluid end body.
 15. The pump system of claim 1, further comprising a measurement device configured to measure a position of the suction and discharge valve members within the fluid end body.
 16. A method of operating a pump system, comprising: pumping pressurized fluid from one or more inlets of a fluid end body into a chamber of a cylinder housing, wherein the pressurized fluid forces a suction valve member into an open position to allow fluid flow into the chamber; and pumping the pressurized fluid from the displacement chamber into one or more outlets of the fluid end body, wherein the pressurized fluid forces a discharge valve member into an open position to allow fluid flow out of the chamber, wherein the suction valve member remains in contact with the discharge valve member when the discharge valve member is moved into the open position.
 17. The method of claim 16, further comprising biasing the suction valve member into a closed position against the discharge valve member via a suction valve biasing member, and biasing the discharge valve member into a closed position against a valve seat via a discharge valve biasing member, wherein a central axis of the suction valve member is aligned with a central axis of the discharge valve member.
 18. The method of claim 17, further comprising securing the suction valve biasing member between a valve guide and a spring retainer via a locking device, wherein the locking device is coupled to the spring retainer and the suction valve member to secure the suction valve biasing member between the valve guide and the spring retainer.
 19. The method of claim 17, further comprising securing the discharge valve biasing member between the discharge valve member and a cover seal disposed within the fluid end body.
 20. The method of claim 19, further comprising measuring a position of the suction and discharge valve members within the fluid end body. 